Techniques have been developed to collect many sets of measurement information by measuring environmental parameters such as temperature and humidity using a sensor module and transmitting the measurement information to an information processing apparatus through a network. The sensor module has the wireless function and constructs a wireless network for transmitting the measurement information. The wireless network constructed using the sensor module enables efficient collection of information. As one such example, a wireless sensor network described in Patent Literature 1 includes a node for transmitting sensing data obtained by a sensor, a router for relaying the data, and a base for receiving the data from the router. In this network, the node appends path information to the sensing data, and the router regularly transmits information about its existence after appending the path information to the existence information. Through the network constructed in this manner, the base that receives information is further provided with the path information together with the sensing data. In this network, the state of the router can be obtained easily.
Another technique described in Patent Literature 2 reduces the load placed on a master device when a transfer path is constructed in a network involving broadcast communications. With this technique, a slave device, which intends to connect to the network, performs broadcast communications and receives a response from another slave device arranged in the surrounding. The slave device intending to connect to the network uses the content of the response data or the intensity of a magnetic field during reception of the response data to determine a communication path to be used, and stores the determined path information. In this case, the master device has no need to store information about the entire network, and thus has less load.